Self-Complementary Bow-tie Antenna Design for UWB Respiration System

Abstract

Ultra Wide Band (UWB) radars are widely studied to be implemented in the medical field for detecting vital signs in humans such as heartbeat and respiration. UWB antenna is an important issue in UWB radar system since the UWB characteristic isn’t only determining form impedance bandwidth perspective, but the suitable UWB antenna design is also required for UWB respiration radar. In this paper, we propose a bow-tie antenna design for UWB respiration radar system with self-complementary structure. The simulation and measurement experiments were conducted to investigate the proposed antenna characteristic and its performance in supporting the radar system in respiration detection process. In the experiment, the Vector Network Analyzer (VNA) is used to modelled the UWB respiration radar. The antenna is realized using FR4 dielectric substrate with relative permittivity of 4.3 and thickness of 1.6 mm. The antenna was design to cover the UWB range from 4–10 GHz. Simulation and measurement results show that the proposed antenna has fulfill the bandwidth requirement. The proposed antenna has a bandwidth within range 2.8 GHz to 10 GHz. Due to the minimum distortion point of view, the S21 result from both simulation and measurement indicate that the antenna has linear phase response. The Respiration radar experiments using VNA shows that the reflected signal from chest wall at exhale and inhale can be identified well using the proposed antenna.